The present invention relates to a fluid injector system for use in cleaning industrial tanks.
Material handling units, such as holding tanks or the like, are used in a wide range of industries, such as the pulp and paper industries, chemical industries, mining and refining industries, and the steel industry. One problem that exists in connection with the use of such holding tanks is that, over time, the liquid in the holding tank can no longer hold the solids suspended therein in solution, and the solids fall out, or are precipitated, and load the bottom of the tank. The settled solids reduce tank capacity, can clog pumps, and, in some instances, lock in valuable capital costs of material.
In order to avoid excessive solids buildup, such industrial tanks must periodically be cleaned. Various tank cleaning methods and devices have heretofore been proposed for use. One such apparatus is disclosed in U.S. Pat. No. 5,253,812. Other techniques have also been used.
Pressure washing of industrial tanks to remove settled sludge from the bottom of the tank has been performed in the past. However, known pressure washing systems have required that the tank be taken offline, or out of service, and drained, in order to expose the sludge for spraying and removal by pressurized fluid. This results in expensive downtime for the tank, presents the problem of where to temporarily store the liquid in the tank (if it has economic value), and presents other scheduling and logistics problems.
The problem to be solved is thus to provide a tank cleaning system that can be used to clean sludge out of the tank without the need to take the tank out of service and/or drain the existing liquid from the tank.
The present invention is directed to an injector system capable of injecting pressurized fluid into a sludge layer settled in a tank, to break up the sludge into pieces small enough to be pumped out of the tank by a slurry pump or to be removed by other removal equipment. The injector system is capable of being used even when liquid is present in the tank above the surface of the sludge
The injector system includes a housing having an injector head disposed at a lower side thereof, and the housing has a fluid feed tube extending therethrough which supplies a fluid to the injector head from a fluid supply source. The injector head is capable of being rotated through 360xc2x0 in a horizontal plane, and has two injectors retained therein which can each be rotated through approximately 90xc2x0, from pointing in a substantially horizontal orientation, wherein the injectors oppose each other, to pointing in a substantially vertical downward orientation.
The housing of the injector system houses a hydraulic system or subsystem including a hydraulic motor and hydraulic cylinder, that powers the rotation of the injector head and the injectors through various mechanical couplings. The housing may be in either a xe2x80x9cstand upxe2x80x9d (vertical orientation) or a xe2x80x9clay downxe2x80x9d (horizontal orientation) configuration. The injector system is preferably positioned and maneuvered around in the tank by a wire based guidance system of the type disclosed in U.S. Pat. No. 5,526,989.
The injector system is designed to deliver pressurized liquid through the nozzles directed at the sludge layer, to break up the sludge into pieces of a size such that the sludge can be removed by a separate slurry pump or other removal equipment. The pressurized liquid may be water or the liquid present in the tank above the settled sludge, or a combination of the two. Alternatively, a liquid which is soluble with the contents of the tank, may be employed. As an illustrative example, diesel fuel may be used in cleaning an oil tank.